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Theory About the Universe Has Its Own Ups and Downs

Just last week two scientists reported that the universe appeared to have an ''up'' and a ''down,'' a startling piece of news for cosmologists because it challenged their fundamental belief that the universe is the same in all directions.

Now the bottom may have dropped out of the universe if two critics are right in asserting they have found a basic flaw in the statistics that support the new finding. But the two researchers are standing by their assertion, and other astrophysicists are waiting for the dust to settle before deciding who is right.

The authors of the claim, Dr. Borge Nodland of the University of Rochester and Dr. John P. Ralston of the University of Kansas, reported that polarized light was twisted through a very gradual corkscrew motion as it crossed the universe, with the degree of twisting being greater in one direction than in others.

Their report, published in the April 21 issue of Physical Review Letters, not only defies current cosmological theory but would also require changes in the textbook theory of electromagnetism. Such a revolutionary finding, heralded in a leading scientific journal, could hardly escape attack, and the first critics have struck with unusual speed.

Dr. Daniel J. Eisenstein of the Institute for Advanced Study at Princeton, N.J., and Emory P. Bunn at Bates College in Lewiston, Me., say there is a statistical flaw in the Nodland-Ralston analysis. Dr. Nodland and Dr. Ralston analyzed polarized light from 160 galaxies that were not uniformly distributed in space. Their critics argue that the way they took account of this nonuniformity created a spurious correlation.

Dr. Nodland and Dr. Ralston say the critics have misunderstood their method. Dr. Ralston also notes that the editors of Physical Review Letters held up their article for two years while six referees examined it minutely for faults, whereas the critics' paper had not yet passed any such scrutiny.

Dr. Ellen G. Zweibel, an astrophysicist at the University of Colorado, said she had just received the critics' manuscript and had not made up her mind which side was right. ''What it boils down to is reading two extremely short, terse papers and trying to decide what was done,'' she said.

She noted that the critics had raised a general objection but had not worked through the numbers to measure the size of the bias they said was there.

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If the Nodland-Ralston result is true, Dr. Zweibel said, it would be ''extremely interesting'' and should be tested by looking at polarized light from more distant galaxies. Their theory predicts that the corkscrew effect increases with distance.

''But if their analysis does not hold up, then the whole thing will probably fade away,'' Dr. Zweibel said. ''So it's important to resolve this issue as quickly as possible.''

The two scientists' point of departure was an idea by Dr. Ralston that would modify the classical theory of electromagnetism. Since the effect he predicted was too small to show up in any laboratory, he had to look for it at cosmological distances. He and Dr. Nodland found that the plane of polarized light traveling through space twisted just one turn every billion light-years, according to their measurements.

Dr. Nodland said that in response to the referees' comments elicited by the journal, he and Dr. Ralston had performed two independent statistical tests of their data. The critics were attacking only one and from an incorrect premise, he said.

Dr. Ralston chided his critics for stepping outside scientific channels by allowing their paper to be made public before other scientists had evaluated it.

''They haven't seen our data,'' he said. ''They came to a very rash deduction based on one scatter plot. Our paper can't be eyeballed and replaced by a set of unsupported assertions with no calculations.''

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A version of this article appears in print on April 25, 1997, on Page A00020 of the National edition with the headline: Theory About the Universe Has Its Own Ups and Downs. Order Reprints|Today's Paper|Subscribe